Water-cooled heat sink and water-cooled system

ABSTRACT

There is provided a water-cooled heat sink including first and second heat transfer channel plates that are stacked and coupled together. The first heat transfer channel plate is provided with a continuous recess that is located in a facing surface thereof that faces the second heat transfer channel plate, corresponds to the coolant channel, and is open at the facing surface, the second heat transfer channel plate is provided with a continuous protrusion, which is fitted into the recess of the first heat transfer channel plate with a gap therebetween, in a facing surface thereof that faces the first heat transfer channel plate, and the first and second heat transfer channel plates are stacked and coupled together to define the coolant channel between the recess and the protrusion.

RELATED APPLICATIONS

This Application claims benefit of priority under 35 U.S.C. §119 to Japanese Patent Application No. 2006-210945 filed on Aug. 2, 2006, which is hereby incorporated by reference.

BACKGROUND

1. Field of the Disclosure

The present disclosure relates to a water-cooled heat sink and a water-cooled system that radiate the heat of a heat generating source.

2. Description of the Related Art

Water-cooled heat sinks are used for radiating the heat of, for example, a CPU (heat source) that generates heat. These water-cooled heat sinks have a coolant channel within a heat transfer block that thermally contacts a heat generating source. Although studies have been made to the use of a spirally formed the coolant channel so as to increase the effective length thereof (see for example, JP-A-8-97337, JP-A-8-204079, and JP-A-2003-234589), the basic concept of using water (coolant) that flows to remove the heat of a heat source that touches a heat sink, performing cooling, is common.

In such a water-cooled heat sink, if the cross-sectional area (contact area with a coolant) of a channel is increased, a heat-radiating effect becomes high. However, if channel grooves are made minute (the number of walls are increased) in order to increase the cross-sectional area of the channel, machinability becomes more difficult, and channel resistance increases.

SUMMARY OF THE DISCLOSURE

A water-cooled heat sink is disclosed in which a coolant channel for allowing a coolant to flow therethrough is formed in a heat transfer body that directly or indirectly contacts a heat generating source. The heat sink includes first and second heat transfer channel plates that are stacked and coupled together. In this water-cooled heat sink, the first heat transfer channel plate is provided a continuous recess that is located in a facing surface thereof that faces the second heat transfer channel plate, corresponds to the coolant channel, and is open at the facing surface. The second heat transfer channel plate is provided with a continuous protrusion, which is fitted into the recess of the first heat transfer channel plate with a gap therebetween, in a facing surface thereof that faces the first heat transfer channel plate. The first and second heat transfer channel plates are stacked and coupled together to define the coolant channel between the recess and the protrusion.

The water-cooled heat sink of the invention can be used for a water-cooled system including a liquid pump having a discharge port that communicates with an inlet hole of the coolant channel, and a suction port that communicates with an outlet hole of the coolant channel; and a heat-radiating unit formed in a channel that connects the outlet hole with the suction port.

In one embodiment, the heat generating source may thermally directly or indirectly contact the second heat transfer channel plate.

There are alternatives in the cross-sectional shape of the recess of the first heat transfer channel plate and the protrusion of the second heat transfer channel plate. For example, the protrusion and the recess may have a rectangular cross-section, a semicircular cross-section, or an oblong shape. Moreover, the protrusion and the recess may have a triangular cross-section.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram of a water-cooled system with a water-cooled heat sink of the disclosure;

FIGS. 2A and 2B are a plan view and a side view of a heat transfer channel plate of the water-cooled heat sink in the water-cooled system of FIG. 1;

FIGS. 3A and 3B are a plan view and a side view of the other heat transfer channel plate of the water-cooled heat sink;

FIG. 4 is a sectional view taken along line IV-IV of FIGS. 2 and 3 in a state where heat transfer channel plates of these figures are stacked;

FIG. 5 is a partially enlarged sectional view of FIG. 4, showing details of a cross-sectional shape of a cooling-water channel;

FIG. 6 is an enlarged sectional view corresponding FIG. 5, showing another shape of the cooling-water channel;

FIG. 7 is an enlarged sectional view corresponding FIG. 5, showing still another shape of the cooling-water channel; and

FIG. 8 is an enlarged sectional view corresponding FIG. 5, showing a further shape of the cooling-water channel.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 is a conceptual diagram of a water-cooled system with a water-cooled heat sink 10 according to the disclosure. The water-cooled heat sink 10 is made of a heat-conductive metallic material, and has a continuous coolant channel 11 inside, and both ends of the coolant channel 11 are connected to an inlet hole (inlet end) 12 and an outlet hole (outlet end) 13 that face the external surface of the water-cooled heat sink 10. The inlet hole 12 communicates with a discharge port 16 of a liquid pump 15 via a suction communication passage 14, and the outlet hole 13 communicates with a suction port 18 of the liquid pump 15 via a discharge communication passage 17. The discharge communication passage 17 is provided with a heat-radiating unit 19 composed of a radiator 19 a and a cooling fan 19 b. A CPU 20, illustrated as a heat generating source, is in thermal contact with the water-cooled heat sink 10. When the liquid pump 15 is driven, a coolant enters the coolant channel 11 of the water-cooled heat sink 10 from the discharge port 16, the suction communication passage 14, and the inlet hole 12. The coolant that has taken heat away from the CPU 20 and thereby has risen in temperature is cooled by the heat-radiating unit 19 in the course of return from the outlet hole 13, the discharge communication passage 17, and the suction port 18 to the liquid pump 15.

The water-cooled heat sink 10, as shown in FIGS. 2 to 4, includes a first heat transfer channel plate 101 and a second heat transfer channel plate 102 that are stacked and coupled together, and an inlet/outlet block 103 having the inlet hole 12. The outlet hole 13 is fixed to the first heat transfer channel plate 101. As shown in FIG. 2, a continuous recess 11 a is formed in a facing surface of the first heat transfer channel plate 101 that faces the second heat transfer channel plate 102. Here, the facing surface is open. The continuous recess 11 a is formed such that it reaches a central portion of the first heat transfer channel plate 101 spirally from the inlet hole 12, and is again guided spirally to the outside of the first heat transfer channel plate 101 and reaches the outlet hole 13. The continuous recess 11 a, as shown in FIGS. 4 and 5, is formed in a rectangular cross-sectional shape. There are some alternatives in the planar shape of the continuous recess 11 a. The illustrated example is an example of the spiral planar shape that is effective for securing a sufficient effective length within a limited space.

As shown in FIG. 3, a continuous protrusion 11 b, which is fitted into the continuous recess 11 a, is formed in the facing surface of the second heat transfer channel plate 102 that faces the first heat transfer channel plate 101. As shown in FIGS. 4 and 5, the continuous protrusion 11 b has a rectangular cross-section smaller than the continuous recess 11 a, the first heat transfer channel plate 101 and the second heat transfer channel plate 102 are stacked together, thereby forming a U-shaped coolant channel 11 in cooperation with the continuous recess 11 a in a state of being fixed with fixing bolts 104. A seal member or an adhesive can be interposed in a portion excluding the recess 11 a between the first heat transfer channel plate 101 and the second heat transfer channel plate 102. Otherwise, joining (laser welding, diffusion joining) between metallic portions may be performed.

As such, the coolant channel 11 is composed of the continuous recess 11 a including a simple rectangular groove, and the continuous protrusion 11 b that is fitted into the continuous recess 11 a with a gap therebetween, and is formed only by stacking the first heat transfer channel plate 101 and the second heat transfer channel plate 102 on each other. Accordingly, the machinability of the water-cooled heat sink is excellent. In addition, the first heat transfer channel plate 101 or the second heat transfer channel plate 102 are further split into two pieces, for example by separately forming continuous protrusions.

Further, when the coolant channel 11 is constituted by the continuous recess 11 a and the continuous protrusion 11 b, the heat radiation performance of the water-cooled heat sink is also excellent. Supposing the second heat transfer channel plate 102 is composed of a flat surface 11 c (FIG. 5) that blocks the continuous recess 11 a, the heat transfer area on the side of the second heat transfer channel plate 102 corresponds to a width s on the open side of the continuous recess 11 a. In contrast, if the continuous protrusion 11 b is formed in the second heat transfer channel plate 102, the heat transfer area on the side of the second heat transfer channel plate 102 increases twice (2×) as long as the protrusion length x of the continuous protrusion 11 b towards the continuous recess 11 a. For this reason, the cooling water that flows through the coolant channel 11 can effectively take away the heat on the side of the second heat transfer channel plate 102. The CPU 20 may be brought into direct thermal contact with the second heat transfer channel plate 102, and may be brought into indirect thermal contact therewith via heat-conductive grease, etc.

FIGS. 6 to 8 show other shapes of the continuous recess 11 a and the continuous protrusion 11 b (accordingly, coolant channel 11). FIG. 6 shows an example in which both the continuous recess 11 a and the continuous protrusion 11 b have a triangular (equilaterally triangular) shape, FIG. 7 shows an example in which both the continuous recess 11 a and the continuous protrusion 11 b have a semicircular cross-sectional shape, and FIG. 8 shows an example in which both the continuous recess 11 a and the continuous protrusion 11 b have an oblong cross-sectional shape (have a semicircular part outside a parallel part). These embodiments can also improve heat transfer performance similarly. Particularly, the triangular shape of FIG. 6 can enhance heat transfer performance compared with the rectangular shape. Depending on the size of the continuous protrusion 11 b′ as indicated by a chain line in FIG. 5, a slit that 11 b′ that increases heat transfer area can be formed. 

1. A water-cooled heat sink in which a coolant channel for allowing a coolant to flow therethrough is formed in a heat transfer body that contacts a heat generating source, the water-cooled heat sink comprising: first and second heat transfer channel plates that are stacked and coupled together, wherein the first heat transfer channel plate has a continuous recess that is located in a facing surface thereof that faces the second heat transfer channel plate, corresponds to the coolant channel, and is open at the facing surface, wherein the second heat transfer channel plate has a continuous protrusion, which is fitted into the recess of the first heat transfer channel plate with a gap therebetween, in a facing surface thereof that faces the first heat transfer channel plate, and wherein the first and second heat transfer channel plates are stacked and coupled together to define the coolant channel between the recess and the protrusion.
 2. The water-cooled heat sink according to claim 1, wherein the heat generating source thermally contacts the second heat transfer channel plate.
 3. The water-cooled heat sink according to claim 2, wherein the heat generating source directly contacts the second heat transfer channel plate.
 4. The water-cooled heat sink according to claim 2, wherein the heat generating source indirectly contacts the second heat transfer channel plate.
 5. The water-cooled heat sink according to claim 1, wherein the cross-sectional shape of the recess and the cross-sectional shape of the protrusion are rectangular.
 6. The water-cooled heat sink according to claim 1, wherein the cross-sectional shapes of the recess and the cross-sectional shapes of the protrusion are semicircular or oblong.
 7. The water-cooled heat sink according to claim 1, wherein the cross-sectional shape of the recess and the cross-sectional shape of the protrusion are triangular.
 8. A water-cooled system comprising: a water-cooled heat sink in which a coolant channel for allowing a coolant to flow therethrough is formed in a heat transfer body that contacts a heat generating source; a liquid pump having a discharge port that communicates with an inlet hole of the coolant channel of the water-cooled heat sink, and a suction port that communicates with an outlet hole of the coolant channel; and a heat-radiating unit formed in a channel that connects the outlet hole with the suction port, the water-cooled heat sink including first and second heat transfer channel plates that are stacked and coupled together, wherein the first heat transfer channel plate has a continuous recess that is located in a facing surface thereof that faces the second heat transfer channel plate, corresponds to the coolant channel, and is open at the facing surface, wherein the second heat transfer channel plate has a continuous protrusion, which is fitted into the recess of the first heat transfer channel plate with a gap therebetween, in a facing surface thereof that faces the first heat transfer channel plate, and wherein the first and second heat transfer channel plates are stacked and coupled together to define the coolant channel between the recess and the protrusion.
 9. The water-cooled system according to claim 8 wherein the heat transfer body directly contacts a heat generating source.
 10. The water-cooled system according to claim 8 wherein the heat transfer body indirectly contacts a heat generating source.
 11. The water-cooled system according to claim 8, wherein the heat generating source thermally contacts the second heat transfer channel plate.
 12. The water-cooled system according to claim 11 wherein the heat generating source thermally directly contacts the second heat transfer channel plate.
 13. The water-cooled system according to claim 11 wherein the heat generating source thermally indirectly contacts the second heat transfer channel plate.
 14. The water-cooled system according to claim 8, wherein the cross-sectional shape of the recess of the first heat transfer channel plate and the cross-sectional shape of the protrusion of the second heat transfer channel plate are rectangular.
 15. The water-cooled system according to claim 8, wherein the cross-sectional shape of the recess of the first heat transfer channel plate and the cross-sectional shape of the protrusion of the second heat transfer channel plate are oblong.
 16. The water-cooled system according to claim 8, wherein the cross-sectional shape of the recess of the first heat transfer channel plate and the cross-sectional shape of the protrusion of the second heat transfer channel plate are triangular. 